Campylobacter isolates from turkeys were genotyped and characterized by their in vitro virulence properties. Relationships between bacterial genotypes and virulence properties were analysed. Isolates were analysed by pulsed-field gel electrophoresis and fla typing. The toxin production was determined on the phenotypic level using a CHO-K1 cell culture model and on the genotypic level using PCR for detection of the cdtA, cdtB and cdtC genes. Although the cdtB gene was detected from 100% of the Campylobacter jejuni and Campylobacter coli isolates we observed three different morphological pictures on the cells. Cytotoxicity was associated with cell distension or cell rounding. All four Camp. coli strains and one Camp. jejuni strain did not produce any cytotoxic changes on the cells. Adhesion, invasion and survival of Campylobacter isolates were determined in a Caco-2 cell culture model. All isolates adhered to and invaded Caco-2 cells, whereas 64.7% of the strains survived for 48 h in the cells. Seventeen Campylobacter isolates from turkeys were classified into four groups with regard to their in vitro abilities. Jackknife analysis revealed a strong association between these groups and genotype clusters. Typing methods have generally failed to identify strains with specific virulence properties. This study suggests that a relationship between subgroups of Campylobacter with common in vitro virulence characteristics and genotypes exist.